help moving from zippy pop to SR700 especially with profiles
Posted on 01/01/2016 1:03 AM
Joined: April 07, 2015
Hi all. I have a question needing help understanding if my techniques will work for fluid bed, I will put subheadings so you can skip sections that might be boring.
Zippy Pop Background:
I have been roasting for a while on a zippy pop, and enjoyed it but eventually burned out. Too much set up, mess, etc in order to do it in a well controlled way. Anyway on the zippypop I used a constant power, pretty high, then brought it down later in the roast, down more, and had to bump it up a little as I hit first crack to keep it moving and eventually down again to get the profile I wanted.
This was because the pot would have alot of heat, and i was putting in constant energy, making it heat up etc.
SR700 with Open Roast basic operations
The provided software only has three heat levels, so I am using Openroast, a program that essentially controls the temperature entering the chamber within plus or minus 10 degrees.
The challanges I have had with fluid bed are:
1. The heat transfers to the bean REALLY quickly
2. If i start with an air temperacture over 1c it goes WAAAYY to fast
3. If raise the temperature suddenly at a point in the roast, the Delta BT will always increase. If the bean has a Ror of X at Temperature Y, and I make it Y+Z then obviously the ROR will have to increase...
4. The probe is extremelly affected by environmental temps, especially early on
I THINK, just an evaluation so far, that exhaust temp is the only way to get bean temp. Also, my observation is that early on it reads way too high. My theory is that the steam being produced by the beans as they heat, combined with the air entering the chamber, is causing for the early exhaust temp to be way too high. However, as the roast progress the steam stops, the volume increases, and the exhaust temp becomes more aligned with BT. Therefore I am currently operating, based on some preliminary observation, that my probe is reading somewhere around 5-10 Degree f above BT from about 300-drop. If you have some information that could help please let me know!
My thoughts, does it work this way?
So basically to make sense of this I am imagining that the air is the pot. The pot in the zippy pop was constantly increasing and that in turn caused the beans to increase gradually. If I replace the pot with hot air then the same idea should apply, the air should be gradually increasing in temperature at a steady slope, and it is this rate of rise that will in turn affect and control the bean temperature.
Thus, rather than starting out with high heat, I set a specific air temperature that will establish a specific ROR, and then as the ROR starts to peak I gradually start to increase the air temperature to reach my desired profile. Is there something wrong with this in practice, or a I on the right track?
Here is an example from my last roast, alot still to improve on it, and some of the microvariance will not be able to be fixed, but some of the larger sings in delta should be able to be fixed with honing the profile. I this case I am measuring the exhaust temperature. *forgot to record First crack end and end of dry might have been marked a little high and is purely sensory based looking for clear yellow almost browning and clear toasting smell, but assuming the probe is about 5-10 off it seems close.
Day attached the following image:
Edited by Day on 01/01/2016 1:14 AM
Posted on 01/05/2016 7:33 PM
Location: Brisbane Australia
Joined: December 31, 2008
It's not unusual to have 6 to 9 minute roasts to second crack on a popcorn popper
Many mechanical ways have been invented & posted to slow the roast down
In the end most popper roasters upgrade to other roaster hardware mostly because of the low weights they can roast
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